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What is the influence of yaw on P-factor?
From William Kershner's “The Advanced Pilot’s Flight Manual”- page 2-17, P-Factor:

If the airplane is yawed, the P-factor effect is encountered. A left
yaw would mean a slight nose down tendency and a right yaw a slight
nose up tendency (you can reason this out).

Unfortunately, I couldn’t reason this out :(
Anyone care to explain?
Thanks!

I added the author, but the question would still benefit from saying what edition is being cited.

As a starting point, you need to thoroughly understand why P-factor tends to make a left yaw torque (in the case of a clockwise-rotating prop, as viewed from behind) when an aircraft flies in a nose-high "angle-of-attack".  Note that by the aircraft's "angle-of-attack", we mean the aircraft's pitch "attitude" in relation to the flight path, not in relation to the ground.  Do you see how this increases the lift or thrust generated by the down-going half of the prop disk, and decreases the lift or thrust generated by the up-going half of the prop disk?  Thus creating extra thrust from the right side of the prop disk and making the aircraft tend to yaw to the left, in the case of a clockwise-rotating prop (as viewed from behind)?  If not, you might benefit from reading the section entitled "P-factor" from John Denker's "See How It Flies" on-line tutorial website.
Once you've digested that, you'll observe that for a mental "shortcut", we can model the effect of P-factor as follows:  think of the spinning prop as a solid disk.  Pick the point on the disk that is "tilted backwards" in relation to the actual flight path.  This would be the top of the disk in the case of an aircraft flying at a high angle-of-attack.  Now rotate your chosen point 90 degrees in the direction that the prop is rotating-- which for this explanation we'll assume to be clockwise, as viewed from behind.  So now you are looking at a point on the right edge of the prop disk, as viewed from behind.  P-factor can be modeled as an extra forward "thrust" or "push" applied to the prop disk at this point.  This will tend to make the aircraft yaw to the left.  Note that this has nothing to do with gyroscopic precession-- it's a purely aerodynamic effect.  This mental shortcut isn't meant to explain why P-factor occurs, just to quickly determine in which direction it acts.
Once you are comfortable with this "shortcut" for figuring out which part of the prop disk will be "loaded up" by the P-factor effect, consider that sideslip tilts the prop disk in relation to the direction of the flight path, just as flying at a high angle-of-attack does.  In a sideslip with the nose pointing to the left of the flight path (ball to the right, yaw string to the left), which part of the prop disk is "tilted backwards" in relation to the direction of the flight path?  The left-hand side.  So if the prop is rotating clockwise as viewed from behind, the P-factor effect can be modeled as an extra forward "push" on the top of the prop disk, and a decreased forward "push" on the bottom of the prop disk.  This will create a nose-down pitch torque.
Kershner could have been more clear in his language here, particularly in relation to his use of the word "yaw".  It's critical to note that we are actually talking about the sideslip angle here, not an actual yaw rotation rate.1  An actual non-zero yaw rotation rate creates a pitch torque in the opposite direction, through gyroscopic precession -- yawing to the left will pitch the nose up.  Just as flying at a high angle-of-attack creates a left yaw torque through P-factor, while pitching the nose down (as when a tail-wheel aircraft lifts the tail during the take-off roll2) creates a left yaw torque through gyroscopic precession. One effect is related to the aircraft's attitude in the relation to the direction of the flight path, and the other effect is related to the direction and rate of change of the aircraft's attitude in space.
Footnotes--

Clearly, the word "yaw" is often used in several different ways in aviation.  Most correctly, it refers to an actual rotation about the aircraft's vertical axis, but it's not uncommon to use it to mean essentially the aircraft's "yaw attitude" in relation to the "relative wind" or actual direction of the flight path though the surrounding airmass-- which is exactly the same thing as the "sideslip angle".  (The term "yaw string" is a classic example of this usage-- and the "yaw string" is sometimes also called the "slip string".)  When Kershner says "if the aircraft is yawed", you should read "if the aircraft is yawed into a sideslip or skid and then held there", or "if the aircraft is allowed to fly in slipping or skidding attitude".

Harvey S Plourde's book "The Compleat Taildragger Pilot" contains a great graph showing the individual and combined effects of all the different factors that contribute a left-yawing tendency during the takeoff roll in a tailwheel aircraft, from the start of the takeoff roll all the way to the moment of liftoff.  Different factors are dominating at different points in the takeoff roll.

I think I got it, that is an amazing explanation.      Basically what you are saying is you are explaining that slight nose down tendency when yawing left, and nose up tendency when yawing right, with the gyroscopic precession, correct?   When I yaw to the left, the left side is backwards, creating more lift/thrust, and adding 90 degrees to the direction of motion, giving an extra push on the upper side of the prop/“disk”, creating nose down.  Opposite for right yaw, right side creating more thrust, 90 degrees is down side of prop creating more thrust- creating nose up. Correct?

@leha007, I think you are confusing two different phenomenons. P-factor and gyroscopic precession are not related to each other, except the resulting motion that you see. The forces that cause each are totally different. The reasons that cause p-factor due to yaw are not the same as the reasons that cause gyroscopic effect. But resultant force may be in the same direction and enforce each other. Such that, yawing left causes nose down in both cases but for totally different reasons and in different amplitudes.

@kolom what explains the nose up when yawing right is the gyroscopic precession though, doesn’t it? Since now the right side of the prop is creating more thrust, creating a force 90 degrees in the direction of motion pitching the nose up. Am I wrong in understanding it that way?

I want to correct my last comment. For clockwise props yawing left causes nose down because of p-factor and nose up because of gyroscopic precession. They may cancel each other out if they are equal, which is rarely the case.

Coming to your question; right yaw causes nose down because of gyroscopic precession and nose up because of p-factor. To confuse you a little bit more; for counter-clockwise rotating props both effects happen to be at same direction. So they complement each other. Maybe, that’s one of the reasons why US prefers clockwise props to minimize side effects.

@leha007 and Kolom -- even though my "mental shortcut" for thinking about P-factor involves a 90-degree shift in the direction of the prop's rotation, it actually has nothing to do with gyroscopic precession.  As I tried to explain near the end of my answer and as Kolom noted in one comment, in some sense P-factor and gyroscopic precession actually act in opposite directions.  However, Kolom, that is true regardless of direction of prop rotation.  They don't act in the same direction if the prop rotates counter-clockwise.  Puzzle through it a little more...

@Kolom -- see comment immediately above--

@quiet flyer- well so what confuses me is if your mental shortcut doesn’t involve gyroscopic precession, how can you use it? Like what “gives you the right” to involve the 90 degree shift in the direction of rotation? Why 90? Why not 180 or 270? Thanks again for clarifying...

@Jeha007 -- just because it works.  Because the answer that is provided, is consistent with the answer provided by the in-depth analysis given in the "See How It Flies" link contained in my answer.  Kind of like the "right hand rule" regarding the direction of a magnetic field induced by a flowing current, in physics.  But in the P-factor case you need to keep in mind that if the prop is turning in the OTHER direction, you'll end up with a different answer-- not a factor in the magnetism example.

To clarify- what confuses me is I understand how Gyroscopic precession can cause nose up/nose down, because the left side or the right side of the prop are generating more thrust, and shifting that 90 degrees in the direction of motion would cause nose up/nose down, but I DON’T understand why P-Factor would cause nose up/nose down, because in my mind P-Factor is a force “generated” on either left or right side of the prop, only creating more left yaw/less left yaw, and isn’t acting up/down. What am I missing here?

Think of an aircraft at a 90 degree left bank, knife edge flight. How would normal p-factor affect the aircraft? For clockwise rotating propellers of course, it would crate a left yaw and causes the nose to drop towards the earth. The same thing happens when you introduce a left yaw to a wings-level aircraft. P-factor moves the nose down towards the earth, so the aircraft pitches down. In both cases the airflow is coming from the same side of the propeller if you can just ignore the aircraft itself. Since the effect is the same,  then resulting action should be the same as well. That’s why left yaw causes slight nose down, and right yaw causes slight nose up.
It’s less prominent because pilots fly just a fraction of flight time with side slip, if they do at all, versus when compared with angle of attack. More over, the pitch change effect due to side slip is not discernible in the noise, e.g. turbulence or trim changes.

I'm going to suggest an edit that would fix at least one error in this answer (last sentence specifically) and also supply some missing "lefts" or "rights". The edit is substantial enough that I'd rather see the author copy and paste it in himself/ herself rather than just make it myself and see if he/ she approves or rolls back.  So here goes--

"Think of an aircraft in a 90 degree right bank, knife edge flight. How would normal p-factor affect the aircraft? For clockwise rotating propellers of course, it would create a left torque as seen by an observer on the ground, causing the nose to pitch down in the aircraft's reference frame.  The same thing happens when you introduce left yaw to a level flying aircraft. P-factor moves the nose down, so the aircraft pitches down. In both situations the airflow is coming from the same side for the propeller in the aircraft's own reference frame, and the resulting pitch torque is the same in a/c

"...and the resulting pitch torque is the same in the aircraft's own reference frame."

( The point being that in knife-edge flight (banked to right) and in left-yawed wings-level flight, the airflow is not actually coming from the same side of the propeller in the earth reference system.  The two cases that are the same in terms of which part of the prop disk gets the extra loading as seen in the earth reference frame, are knife-edge flight, and wings-level flight with no yaw/slip but a high angle-of-attack.) Apart from this one specific error, and the need to guess at which direction of knife-edge of flight is being described, this is a really nice concise answer.

Nice inputs. Added one more paragraph.

It is like an helicopter. If it hovering in one place the blades will meet the airflow at the same angle. The forward speed of the helicopter make them to change their AOA(increase) for half of the circle of the rotating blades (the retreated blades)to compensate (bite more air for that) asymmetric vertical pulling . But the aircraft propeller  don't have swash plate to help with this so P- factor bites you. Means that the half of the disc will help you to have a roll rate better for leftside due to the Increased AOA to the one side of the propeller , but when you try to do it to the right side  must use more resources (force on the stick) and rudder That why it is take off trim for rudder @6 degree( angle-of-attack is more than in cruising. Hope you're understand the analogy. It is about the amount angle-of-attack of the propeller  for only half of the rotation when we put the nose up atitude (P factor). it is not identical. About the nose down attitude that came from the  aircraft wings. The yaw change the angle of  incidence for airflow meeting them(specifically if they are straight wings, not sweept)

" About the nose down attitude that came from the aircraft wings."-- that is clearly not what the author was talking about--

He ask about the tendincy of the wings to dip on one side but on other side. From here's that tendincy to be more prone to roll on one side than the other. Guess his question it's about gyroscopic precession.

There are two factors that will make the difference in (single) propeller aircraft. One is airflow from the propeller that will be more speedy on the root of the left wing, than the airflow over the right side (slower), and two it is about the left side of the rudder that have same effect (airflow coming on the left side has an effect on the aircraft),That it is way aircraft engine is slightly offset by the factory in longitudinal axis.

Again, while those effects may be real, they are clearly not what the author is referring to.  Are you really familiar with the term P-Factor?  See the "See How It Flies" link cited in my answer.


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What determines the direction of rotation for counter-rotating propellers?
As Wikipedia and other sources make clear, most twins with counter-rotating props are configured with the left (#1) prop turning clockwise (as viewed from behind the plane) and the right (#2) prop turning counterclockwise. But there are significant exceptions, such as the P-38. What the sources do not make clear is the reason for the exceptions. There are a few vague comments about the P-38 having "unsatisfactory" handling as originally configured with the common setup, but nothing that helps me understand what aerodynamic or other issues might make a P-38 or any other plane a candidate for reversing the rotation directions. I realize that there are potential issues with coupling to tip vortices if the engines are near enough to the wingtips. And I assume that there might be effects related to air impinging on the fuselage, or FOD from stuff entrained in the airflow during ground ops, or maybe issues with where ice being slung from the prop blades impacts other structure. But I am wondering if there is a more general aerodynamic principle which drives the rotation direction decision.

Most twin-engine aircraft with counter-rotating propellers have the rotation set up so that the propellers are rotating inward towards the center at the tops of the propeller arc.

This configuration reduces the P-Factor effect at slow speed high angles of attack, and eliminates the "critical" engine that is present on multi-engine aircraft where both engines rotate in the same direction.
Conventional Multi engine propeller aircraft (both clockwise rotation)

The original XP-38 (X=Experimental) had "inward" counter rotating propellers but only flew a few times before it was destroyed in a crash.

There were some tail buffeting problems identified with the XP-38. While trying to solve the tail buffeting problems, various wind tunnel tests were conducted. Some of these tests were done with "outward" rotating propellers.
These tests showed that "outward" rotating propellers did not reduce tail buffeting BUT they did reduce power on/power off pitching moments, and therefore made for a more stable gun platform.

"The P-38 props rotate in the direction they do for the simple reason it reduced the power on/off pitching moment, thus making for a more stable gun platform" - Kelly Johnson, P-38 designer.

The tail buffeting was eventually solved by fitting large leading edge fillets at the wing/fuselage interface.
The YP-38 (Y=Prototype) and most subsequent versions of the P-38 retained the "outward" counter rotating propellers. This in effect made both engines "critical", but combat performance was more important that low speed performance.
So while most aircraft with counter rotating propellers have "inward" rotation, a few do have "outward" rotation to gain an operational advantage.

It was really the F-22 of its age.  I once knew a test pilot that flew B25s in WW2 and came back to Canada and his first flying job in the late 40s was flying a P-38 with a company called Spartan Air Services doing photo surveys in the Canadian arctic (Spartan also used a DH Mosquito).  He said it flew like a jet.

Maybe I'm being thick, but I don't understand things any better after reading this. Obviously airflow will be different for the two options, but how does that actually affect the aircraft?

P-Factor means that at high angles of attack, the propeller will have more thrust on one side of the propeller disc. This is because the down going blade has a higher angle of attack on the air. If the down going blades are on the outside of the disc (outward rotation) the turning moment will be higher than with down going blades in the inside (inward rotation). Refer to the "both clockwise rotation" image above.

There are two considerations.
Two parallel vortices will tend to move upwards if the air flow between them is upwards.  You can think of it as each 'blowing' the other upwards.
This suggests the P-38 configuration maximises lift. I am not convinced but I don't have access to the software to know either way.  Nor did they.
The second consideration concerns one of the reasons for having two engines - the ability to fly on one.
This suggests the almost universal decision to let the dead weight engine help provide the torque needed to turn the working propeller rather than adding to the lift the unpowered wing has to provide.

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Are there any single-pilot aircraft certified in the Part 23 Commuter category?
Is it possible to certify an aircraft under FAR 23 Commuter Category with single pilot ops only? Like, there is just one seat in the cockpit and up to 19 passengers.
Does anyone know of such an aircraft flying?

Your title and your question don't match, but I'm sure the answer to both is "no".

The Metro 23 is called the "23" because it's a part 23, amendment 34 plane.

It looks like it's possible but not common. There's an STC for the Twin Otter that authorizes single-pilot operations in the commuter category if various upgrades have been made. At least, that's my reading of it:

The Twin Otter DHC-6-300HG™ type rating designation is DHC-6HG and may
  be operated with or without a second in command (SIC) with certain
  limitations. The Airplane Flight Manual Supplement (AFMS) lists
  equipment that must be installed and operative to operate the aircraft
  single pilot.

And:

FAA STC SA02682LA incorporates upgraded engines, upgraded propellers,
  increased maximum takeoff weights (MTOW), structural and aerodynamic
  modifications, and the aircraft category and design characteristics
  were updated to Title 14 of the Code of Federal Regulations (14 CFR)
  part 23 commuter category.

HondaJet is certified for single-pilot operation for Part 23. Note that 14 CFR Part 23 Amendment 64 and later removed Utility, Acrobatic, and Commuter Categories and now refer to all of them as Normal Category.

The Phenom 300 is certified under Part 23 and you can be typed as single pilot in it.

Wikipedia lists max. 6 passengers...

The 300 is certified for up to 10, Wikipedia is wrong again.

Florida Flight Center says

CE-501SP and the CE-551SP are FAR part 23 certified aircraft. Both of
  these airplanes may be flown single pilot without a waiver as long as
  your checkride was completed in one of these aircraft to single pilot
  standards.

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Can liquid hydrogen be pumped directly into a jet engine without a heat exchanger? Is it burned as a gas or a liquid in the combustion chamber?
This NASA research paper on H2 engines includes a diagram of Wesley Kuhrt's 1956 design for a hydrogen-fuelled engine, which has no heat exchanger:

(Image by United Technologies Corporation, via NASA.)
But, later on, it also has two diagrams showing hydrogen-fuelled engines with heat exchangers for warming the hydrogen before use; first, a Pratt & Whitney JT3C (J57) modified to burn hydrogen instead of kerosene:

(Image by Pratt & Whitney, via NASA.)
followed by the Pratt & Whitney 304, an engine designed from the start to run on hydrogen:

(Image by Pratt & Whitney, via NASA.)
In a jet engine using liquid hydrogen for fuel, does the hydrogen have to be warmed (presumably using a heat exchanger) and converted to a gas before it can be introduced into the combustion chamber, or can it be pumped in and burned straight as a liquid?

Please [edit] to put the question in the actual question, not just the title.  Also, the image is too small to see well, can you link a larger copy?

Closely related, maybe a dupe?

Also, please cite the full details of the NASA paper.

In order to mix with oxygen and burn, hydrogen must be gaseous. If it is injected as a liquid, it must evaporate first, needing a longer combustion chamber.

And what did the NASA research paper say or not say specifically that led to you asking this question?

i have added the research paper pls check. in that one its mentioning a heat exchanger through which h2 flowing. i think like sabre engine

Hydrogen has to be in gaseous state to burn. The boiling point of hydrogen is ~20 kelvins, while oxygen boils at about 90 kelvins and freezes to solid at ~54 kelvins. It is therefore impossible to mix these two for combustion if hydrogen is in liquid state.
A non scientific answer to pumping liquid hydrogen directly to the combustion chamber is, that it will not work, because the evaporization of hydrogen would bind too much energy from the compressed air, thus cooling it and lowering the pressure to a state that no longer can support efficient combustion.
However, as elements might work in surpising ways under pressure, I'm not 100% sure.


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What is the difference between the V-shape tail and the straight tail on the Beechcraft Bonanza?
In one of the answers to the question which aircraft is the oldest in production, the
Beechcraft Bonanza is mentioned. While reading the Wikipedia entry on this interesting plane, I noticed that there are some models with a V-shape tail and some with a more conventional tail.
What is the difference between the two designs?
 Source: Wikipedia
and
 Source: Wikipedia

V-tails have been fashionable in the Fourties and Fifties, and the claim was that they would cause less drag than an equally effective conventional tail. This has two reasons:

Average chord length is longer, so the Reynolds number of the airflow is higher, causing relatively less friction drag.
Instead of three surface-fuselage-joints, the V-tail has only two, so less interference drag is created.

Flight testing of V-tails showed only marginal advantages, and in damping they are less effective than a conventional tail which is dimensioned for the same control effectiveness. The control effectiveness of a control surface is proportional to the cosine of the V-angle, but the damping characteristics go down with the square of the cosine.
@nimbusgb mentions the tendency of the V-tailed Bonanza to fishtail: That is a consequence of too little lateral damping.
Also, when a combined elevator-rudder input is commanded, the V-tail will produce a very high deflection on one side, while the two commands will cancel out on the other side. This will reduce overall control power in cases where a combined elevator-rudder input is commanded over what is possible with a conventional tail.
Even the glider designers, who had enthusiastically tried out V-tails, have now returned to conventional tails (more precisely, T-tails) because the expected benefits did not materialize. And glider designers will try anything to improve the aerodynamic quality of their designs.

V-tail production ceased in 1982. Possibly due to a perception that they were less safe than a conventional empennage.

The model 35 Bonanza series (1947-1982) had a V-tail
The model 36 Bonanza series (1968-present) had a conventional tail.

There was a self-serving faction in general aviation, though, that went on a crusade to demonize the V-tail because of the in-flight structural failures.
Grist for the mill was the fact that Bonanzas with regular tails seldom had structural failures. They did have just as many loss of control accidents. The difference was they were in one piece a millisecond before becoming thousands of pieces after a collision with the ground. The V-tails didn’t make it to the ground in one piece,

From What was wrong with V-tail Bonanza pilots?

and no doubt "rationalising the product line" also played a part. Why produce 2 effectively identical models, the only real difference being the shape of the tail plane? (and with one of them having a bad rep as accident prone, the choice which to stop making becomes easy).

Additionally, the wing was moved back on the A-36 to provide a better aft-CG limit, much harder to exceed. The shorter models even had ballast in the front to counter that, and are generally not able to have the lighter MT props without serious CG issues.

The technical stuff in other answers is right. The other difference is that the V-tailed Bonanza's tended to 'fishtail' slightly in the cruise.
If I recall correctly, V-tails are not as spin resistant as conventional tails.
My dad flew a Standard Austria for a time (early V-tail sailplane) and it was very definitely prohibited from intentional spinning. Dad tried it once and told me it took about three turns before it would recover.

Ahh - Standard Austria! Maybe you shouldn't spin it, but it definitely was well suited for loopings. At the occasion of the first flight with the finished prototype of the Standard Austria, the pilot started to fly loops. After the third, he asked the designer over the radio: "Notice anything?" - "Yes, you're climbing" was his answer. Thereupon the pilot replied: "That's how you can climb in thermals, too!".

I think you're being too kind in describing the V-tailed Bonanza's tendency to fishtail as 'slightly'. I'd up that a couple of notches, and in turbulence it was just plain unreasonable in my opinion.

V-tails DO NOT fishtail any more than the short body Bonanza 33. The 36 doesn't fishtail simply because it is longer.  It is the short coupled tails on the 33 and 35 that cause the fishtail, not the configuration of the tail.

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Why does the Mitsubishi MU–2B have its own SFAR?
The Mitsubishi MU-2B has a very long & detailed SFAR 108 that details the trained and currency requirements for anyone who wishes to manipulate the controls of the plane. I'm wondering what incidents or accidents and unusual handling characteristics required a Special SFR for this plane.

I don't have all the info, but iirc it stems from handling characteristics of not having ailerons.  Spoilers are used for roll control.  The accident rate has historically been pretty high as well.

Since the MU-2 weighs less than 12,500 lb, a type rating is not required to fly the plane, so pilots only need a multi-engine rating. However, it is a high performance pressurized aircraft that requires more skill to fly. Mitsubishi Heavy Industries asked the FAA to create a type rating requirement for the MU-2, but the FAA decided on creating the SFAR instead, which is more strict than a type rating, especially in the amount of training specifically required.
Research showed that the accident rate of the MU-2 from 2001 to 2005 was not really exceptionally high compared to aircraft of similar size and performance. While the accident rate was higher than some, it was also lower than others. However, the FAA received a lot of pressure to create a rule for the MU-2.
Regardless, the accident rate has gone down significantly since the FAA created new regulations for the plane.

According to Wikipedia (or at least my reading of the article) http://en.wikipedia.org/wiki/Mitsubishi_MU-2
It looks like there were a lot of incidents in the plane, enough that the FAA seems to have investigated the plane specifically and now advises/requires some special training for it. As any government agency would they also issued lots of paperwork as a result thus your findings.

The MU-2 has had a very bad safety record. From various sources I've talked with over the years, if you lose an engine, you need an excessive amount of altitude to recover. Various design issues I've heard are related to it, from possibly overpowered engines, to short wings. All these things coupled basically put the FAA to put in a Special rules for anyone wanting to fly the MU2. Same with the other SFARs, there's usually been a rash of incidents outside of what's normally taught for the category/class, that requires special or additional training.

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How safe is the Beechcraft 1900?
While reading the tragic Accidents and incidents section of this Wikipedia page, I began to wonder how the Beechcraft 1900 ranks for safety.
The page describes 22 known severe accidents and incidents involving the Beechcraft 1900.  According to the article, there were 695 of the aircraft built, with just 341 in service as of July 2015.  That's less than half.
How does one compare these statistics to the norm?  How does the Beechcraft 1900 rate when it comes to safety?

If you would care to read the description of those incidents listed on Wikipedia, you would realise that almost none of them were caused by failures of the aircraft. They were mostly caused by pilot error, weather conditions, etc. - something which is definately not unique to the B190

@J.Hougaard, the trouble is that on Wikipedia, most of the accidents don't have a description. They do on ASN, though.

@J.Hougaard "Pilot error" can be an error of the pilot, or can be indicative of a poorly designed cockpit.  "Weather conditions" can be deciding to fly in inappropriate conditions, or failure of the aircraft to perform.

Also note that they entered production 34 years ago, and the newest ones are 14 years old. A lot of the aircraft no longer in service are due to age, not accidents.

Any airplane operated in a single pilot IFR environment flown on night freight routes in all weather conditions by naively risk tolerant low time pilots working for slipshod fly-by-night operators will have a checkered safety record.  The 1900, like the SA227, C208, Dash 8, and F27, is a really good plane.  The pilots are the weak link, as always.

I would say that it is a reasonably safe aircraft, but, like most aircraft of that class, often operated in unsafe conditions.
The Wikipedia page does not have description for many of the listed accidents, but you can turn to the Aviation Safety Network which does.
There are 41 total hull losses listed there. From them:

Most common type of accident is controlled flight into terrain. That has nothing to do with the type and everything with operating to/from remote airports in mountainous terrain with limited choice of navigational aids around.
Then there are quite a few collisions, both midair and on the ground. That also has nothing to do with the type and much with operating at smaller fields often under VFR and without any radar.
Then there were several accidents where pilots mishandled engine failure. The aircraft is capable of flying on one engine and it had to be demonstrated during certification, but the pilots have to follow the correct procedure and may easily lose control if they don't. This kind of accident is more common in turboprops than in jets, but it does not seem to be more common in B1900 compared to other turboprops.
Only the three accidents that were contributed by improper installation of elevator or elevator trim control cables really have something to do with the specific type. They still have a lot to do with operating by smaller airlines and maintaining in smaller facilities with less experienced staff.

So no, the relatively long list of accident does not suggest any serious problem with the type.
Also, the accident rate and types are similar to the other types used in similar operating conditions like DHC-6, EMB-120, L410 or Do-228.

Thank you Jan.  Very helpful analysis.  I do wonder if cockpit design has anything to do with some of those accidents.

@RockPaperLizard, I don't think. That kind of thing is analysed when investigating accidents involving loss of situational awareness, but I didn't notice any mention for B1900. Also the instruments and cockpit layout are very similar between similar aircraft and there is no advanced automation here.

" there were several accidents where pilots mishandled engine failure." -- This reminds me of the joke, "In the event an engine fails, the other engine will get you to the site of the crash."

@WayneConrad You usually even get there before the NTSB does!

@WayneConrad, that joke is mainly about light piston twins which have looser requirements and many indeed don't have enough power to maintain altitude on single engine. But aircraft over 12 (or 9? I am not sure about the limit) have to demonstrate being able to climb out on single engine for certification.

@JanHudec -- anything FAR/JAR 25 needs to be able to climb out on a single engine

@JanHudec  Quick question: Over 12 (or 9) what?

@RockPaperLizard, ah, passengers.

@JanHudec For part 23 certified aircraft that you may be referring to, the more significant factor is not seating, but Vso of 61 Kts or less. For these aircraft, the engine inoperative climb gradient must be determined, whether positive or negative.

The Beech 1900 aircraft was a sound, well made commuter aircraft; now the list of accidents is misleading.  Reviewing the list finds many occurring while the aircraft is being used for bush flying in extreme parts of the globe.  This is not surprising considering a lot of bush flying involve operating out of remote airports in extreme temperature ranges, high winds, poor weather and with limited ATC and other flight resources for the crew, I'm not surprised the accident rates are fairly high for this aircraft; it does not appear to be attributed to a design fault.
Similar results are obtained from a study of accidents for the Bombardier Dash-8, the Fokker F27 Friendship, and the Cessna C208 Caravan, all of which are fine aircraft commonly used for commuter operations in remote sections of the planet.

The DHC-8/Dash and F27 are both larger and not used in as harsh conditions as the B1900. And yet even they (and the comparable ATR42/72) see a lot of accidents related to poor operating conditions.


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Why is the nacelle outlet of the tail engine of the L-1011 Tristar lower than the engine itself?
I've noticed that the nacelle outlet of the Lockheed Tristar is situated below the engine itself. It is at the end of the fuselage. The nacelle outlet of the tail engine of the DC-10 on the other hand, is at the same height as the engine. Why did Lockheed choose to lower the nacelle outlet? Perhaps this picture will help show you guys what I mean.

given the shape seen in the photo, I suspect that is the inlet to be above the engine, not the engine to be above the outlet. nice question nevertheless.

The Boeing 727 has the same arrangement. It used to be called an S-duct. Anecdotally I was told that after the the 727 Boeing decided that never again would they use an S-duct.

The S-duct was actually more common than the straight-through design, as the DC-10 and MD-11 were the only major designs to use it

As Federico points out, the engine is located directly in front of the exhaust portion. This is true for almost all engines with ducted arrangements. It's much easier to duct the cool, slow intake air to the engine than duct the hot, fast exhaust air away from it, for both temperature and drag reasons.
In this cutaway you can see the intake duct leading down to where the engine is:

Source
Putting the exhaust nozzle lower allows more room for rudder above it. Putting the nozzle higher, like on the DC-10 series, means the rudder is pushed higher up the tail.
This arrangement keeps the rudder as close to the vertical center of gravity as possible, which reduces the stress on the tail and limits the rolling motion induced by the rudder. It also keeps the engine forces close to the vertical center of gravity. This configuration also allows the supports to tie in to the existing structure at the rear of the fuselage. Placing the engine further up the tail would add surface area (and therefore drag), and require additional structure to support the engine above the fuselage.

Thank you for the answer. But why didn't McDonnell Douglas use the same feature on the DC-10?

Simplicity, increased usable fuselage volume, reduced vibration transfer to the cabin, easier access to the engine without taking the back of the airplane apart... these are only a few good reasons I can think of not to use an S-duct design.

I believe that if you ask anyone that has worked on a DC-10/MD11, 'easier access to the engine' will not be high on their list of pros for this engine placement.

You might add that the lower engine location will cause less pitch trim change with thrust changes.

@PeterKämpf, not necessarily, because of the two other engines under the wing. I remember reading that DC-10 was remarkably pitch neutral to thrust changes. But you would be right for the more common tri-jet configurations like 727 or Tu-154.

@Zeus With my comment I was referring to the middle engine - of course, when there are more engines on the plane, and their thrust causes pitch changes, the opposite pitch change of the middle engine will cancel that out. But that was my point: The high engine location does cause pitch changes which will be reduced by moving the engine down, Tri-Star Style.

Bird ingestion stats might be interesting as the tail engine may be more protected.  Tri-jet 787 might be better for high/hot environment, heard 2 engines not quite making it (from Las Vegas).

This arrangement of placing the engine intake duct above the fuselage is called S-duct (Thanks Terry).
The answer of why would be it is how it was designed, probably as a differentiating feature. This is vaguely mentioned here:

... a small vertical fin [is] between the bottom of the middle engine
  intake and the top of the fuselage.

From the pictures below (images' source), it appears that what Federico stated appears to be true.

I have discovered some more information regarding the S-duct design in an L-1011 marketing book.

S-Duct Payload Benefits
  The S-duct center engine location benefits payload by its lower fuselage weights. It allows a longer constant fuselage section thereby adding seating space. The more effective rudder allows the engines to be located further outboard on the wings and provides an optimized center cabin door location. The exhaust efflux provides an effective fineness ratio increase and hence reduces drag.

Center Engine Position
  In the S-duct arrangement the engine is 10 ft. lower than a fin mounted engine. This permits easier access for maintenance or engine changes.

The 'nacelle outlet' you speak of is actually Engine #2.  It is fed air via an 'S' shaped duct running through the tail section of the aircraft, starting at the dorsal intake just forward of the vertical fin.


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What is a ramjet?
What is a ramjet? Was it used on the SR-71 Blackbird?

relevant: http://aviation.stackexchange.com/questions/9066

and the SR-71's engines are not ramjets: http://en.wikipedia.org/wiki/Pratt_%26_Whitney_J58

If you want to show a ramjet, please pick the D-21. It used the Marquardt RJ-43 as its engine, a true ramjet. The SR-71 is a less fitting example.

The SR-71's engines are not pure ramjets (which cannot function below a certain speed because there is no mechanical compression mechanism), but at top speed a feature called compressor bleed bypass diverts some of the compressor stage airflow directly to the afterburner instead of going through the turbojet. This cools the afterburner allowing for sustained operation, and increases the efficiency of the afterburner itself, making it the dominant thrust-producing portion of the engine. Because this bypassed air is directly fueling the afterburner, the J58 is referred to as a "partial ramjet".

A jet engine compresses air, heats it by mixing it with fuel and burns it, and lets the heated air escape at the end, where it accelerates to more than its initial speed in a convergent-divergent nozzle because the density of the heated gas is lower, thus needing a higher volume at the same pressure.
By converting the kinetic energy of the flow into pressure (potential energy), the intake creates high-pressure air to feed the engine. This is called pressure recovery and increases with the square of flow speed. Please see below for a plot: This puts a pressure of 1 at Mach 0.5, which is on the high side for flow speed near the compressor face in a jet engine intake.

Note that in static conditions the air needs to be accelerated, so the intake pressure is only 84% of ambient pressure, and at Mach 0.85, the maximum speed of airliners, the intake pressure is 1.37 times higher than ambient pressure. But at supersonic speed things take really off: Pressure recovery for the Concorde was already 6 at Mach 2.0, and for the SR-71 it was 40 at Mach 3.2. If you want a more mathematical approach, the equation for isentropic compression gives: $$p_0 = p_{\infty}\cdot\frac{(1.2\cdot Ma^2)^{3.5}}{\left(1+\frac{5}{6}\cdot(Ma^2-1)\right)^{2.5}}$$
The odd exponents have to do with the ratio of specific heats $\kappa$ of air. 3.5 is actually $\frac{\kappa}{\kappa-1}$ and 2.5 is $\frac{1}{\kappa-1}$. Real compression ratios are slightly below those of the ideal isentropic compression due to friction, but not by much.
The exact equation used for the plot above is produced by calculating the ratio to the intake Mach number directly, this time with $\kappa$ = 1.405:$$\frac{p_{intake}}{p_{\infty}} = \left(0.2025\cdot Ma^2 \cdot\left(1-\left(\frac{Ma_{intake}}{Ma_{\infty}}\right)^2\right) + 1\right)^{3.469}$$
Thus, you get already the compression ratio of a J-47, an early turbojet engine, at Mach 2 and that of a GE90, a modern turbofan engine, at Mach 3.2. Beyond that, it does not make much sense to complicate the engine with turbo machinery - just let the ram pressure give you the compression for thrust generation. You need, however, speed up the vehicle by other means first, because the possible thrust is proportional to the pressure recovery, or the square of airspeed. No speed, no thrust!
You might have read claims that the J-58 of the SR-71 was a ramjet. This is only half true. Below Mach 2 it worked as a regular turbojet, but it had bypass tubes which ducted some air from the fourth stage of the compressor around the later compressor stages, the combustion chambers and the turbine directly into the afterburner. Now some of the air was compressed in the intake and fed directly to a combustion area and through a convergent-divergent nozzle, so this part worked like a ramjet. Some of the air, however, was still passing through the core engine to keep it running, though.
A better example for a ramjet-powered plane is the Lockheed D-21 reconnaissance drone, which used a Marquardt RJ-43 ram jet for propulsion. Its cruise speed was Mach 3.7, back 50 years ago! See below for a picture (source).

Note that the same trick which makes a ramjet possible can be used to reduce cooling drag for high-speed piston aircraft. A well-designed cooling duct is slowing and compressing incoming air and heats it by letting it flow through a radiator. The heated air has a higher exit speed, resulting in jet thrust which can compensate cooling drag at higher speeds. The Republic XF-12, a much underappreciated design, made exemplary use of this technique.

For the Poetry majors among us, could you include an explanation of what "pressure recovery" refers to? Thanks!

Thinking a bit more about your closing remark on heating air to generate thrust I was thinking about using the same approach on a turbofan. Do you know if there have been any experiments with exchanging heat from the air after the compressor stage to the bypass flow? This could lower the temperature at the inlet of the combustion chamber, thereby increasing the thermodynamic efficiency of the jet core. The extracted energy can generate additional thrust by heating the bypass stream.

@DeltaLima: Interesting concept! All I remember are plans for doing something similar on the T-56 for the P-3. The mechanical complexity was too big in the end, so this concept was dropped. In your turbofan idea the hot and cold flows would be next to each other, so complexity might be manageable. You will need a big volume, however, because heat exchange is more efficient at lower flow speed. I guess the volume demand makes this impractical.

Another reason to want lower speeds is that the cooling air will otherwise have and increasingly high Mach number.  I am not the first to think about this concept though, I've found several papers.  The words intercooled and recuperated are used to describe it. There has been some theoretical work on it in the past 5 years but I could find any practical experiments.

So I take the simple conclusion is: ramjet = jet engine without compressor?

@kevin: … and turbine, yes. Basically it is a jet engine with intake, afterburner and con-di nozzle.

@DeltaLima There are experimental engines that use the fuel (or coolant) to cool the intake air. Mostly for various surface-to-orbit concepts. I guess for anything else the added mass makes it impractical. Similar issues might be blocking your suggestion, the gain might not be worth it for subsonic aircraft. And with Concorde gone that is pretty much everything flying. So Peter is almost certainly correct.

@DeltaLima Clarifying why I was talking about subsonic being an issue. More energy the engine consumes bigger the possible gain. An engine with higher velocity exhaust needs more kinetic energy for the same thrust. Faster aircraft need higher exhaust velocity. So faster the aircraft ismore it can benefit from improvements in energy efficiency. Slower the aircraft, slower the optimal exhaust speed is, which means less energy consumed per volume, which reduces the gains from making a more complex engine to improve energy efficiency.

The ramjet is conceptually the simplest jet engine. It is a duct where air is burned creating a hot jet that provides thrust, it is known aero thermodynamic duct as it is no more than a duct where a thermodynamic cycle is performed.
They are no more used for airplanes, as it can not provide thrust at zero airspeed -since he does not have any compressor within the diffuser- and modern turbofan is much more efficient.
It is composed by a diffuser , a burner and a nozzle , it uses dynamic compression of ram air within its inlet and then the hot jet expand in a convergent-divergent nozzle as it is supersonic.

Airplanes like the Blackbird used a ramjet to reach higher mach speed by starting the ramjet when the where already subsonic.

the blackbird did not use ramjets

@Federico, the P&W J58 engine was essentially a ramjet wrapped around a turbojet.  At high speeds, only enough air flowed through the turbojet core to keep it spinning; most of the air bypassed the core to the afterburner, which functioned as a ramjet.

@Davide, the ramjet is the conceptually simplest jet engine.  Actually building one is a feat of advanced engineering.

"No more used"? This makes it sound as though they were quite popular in the early days of aviation and fell out of favor, which isn't even slightly correct; only a few aircraft have ever managed to make use of a ramjet, and most of those were pure research -- research that continues today, albeit usually on scramjets.

Take a look here
but the short answer

A ramjet, sometimes referred to as a flying stovepipe or an athodyd (an abbreviation of aero thermodynamic duct), is a form of airbreathing jet engine that uses the engine's forward motion to compress incoming air without an axial compressor.

In other words it uses the thrust it generates to compress the on coming air by "ramming" it into the engine. Since they have no way of drawing air in they do not work in a static (not forward moving) situation. They often work best at supersonic speeds. Aside form the device used to pump fuel into the engine they essentially have no moving parts.

What makes them more efficient at higher speeds?

I dont know enough about them to comment but that may warrant a question on its own.

A ramjet is a jet engine in which ram air pressure, generated by the forward motion of the air vehicle is employed to compress air before fuel is mixed with it and burned to produce thrust through an increase in temperature and pressure of the expanding gases. This means that a ramjet cannot generate static thrust or operate efficiently below a certain airspeed. Ramjet engines are usually designed to operate at supersonic speeds. A scramjet, or supersonic combustion ramjet is a ramjet in which the airflow through the engine combustion section is supersonic.


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Does CG location affect the stability of the Dassault Falcon 7x while on the ground?
Can any one please explain me the basic static stability of Falcon 7x on ground at aft most CG which is 38.5%MAC=12.63498m ... because as per my hand calculations i m getting around 2% load/weight on Nose landing gear... is there something wrong with my calculations or the CG doesn't really affect the aircraft stability...?
I have used following method to determine the load
$$Fn_{min} = \frac{Bm_{min}* W}{B}$$
$Fn_{min} = 4090.817398$, % of load $2.093923332$ where $Bm_{min}$ is distance from Main Landing gear to the aft most cg = $0.201 \mathrm{m}$, $W$ is the design limit weight $=19915 \mathrm{kg}$, $B$ is the wheel base $= 9.5644 \mathrm{m}$.

2% weight on nose wheel sounds plausible.
Almost all weight of an aircraft must be on the main wheels. Otherwise:

the elevator would have to be huge to generate enough force to lift the nose wheel off the ground on take-off and
on landing as the main gear contacts runway first it would create strong moment that would slam the nose into the ground.

See also Why do planes always land on rear wheels instead of the nose wheels?.
I've seen values like 4% weight on the nose wheel, so 2% for CG at aft limit makes sense. It is still enough to keep the aircraft level and leave some efficiency of the steering.
And yes, loading mistake can make an aircraft tip over on the tail:

(copied from this answer; original source)

I once climbed onto the tail of an RAF Hunter to spray paint a squadron zap which ended up like that.  It took a few of us pulling on the nose gear to get it back down.  Thankfully, the tail was over the grass at the side of a pan and damage was superficial.

@JanHudec I would like to thank you for all your help and support in editing, formatting and answering my question, also wanted to request if you could share your profile details with me as I could mention you in my thesis... Thanks


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How reliable are stick shakers?
I've read many accident reports, and seen reconstructions, where instrument failures, disagreeing sensor sources and auto pilot faults have led pilots into believing that they are over speeding when they are not (think AF447), are descending when they are actually climbing etc.
It seems that in all cases where this has led to a stall, the stick shaker has activated but the PF does not take the correct immediate action for stalls, instead continuing to believe the erroneous information they are being fed.
I understand the psychology of why this might be but is does strike me that many lives would have been saved if power up nose down had been applied.  I've not found a case yet where the shaker was wrong. This leads me to wonder...
How reliable are stick shakers?  Should they always be trusted?
Some older types even had an automatic stick pusher but this does not seem to be present in modern designs.  Is this a consequence of shakers not being infallible?

The stick pusher is still there, it didn't go away.  Stall recovery practice on the EMB-145 was to take it to the shaker and recover with minimal altitude loss without the pusher activating or secondary shaker activation.

@ratchetfreak  I edited my question slightly.  In all cases I have read, the shaker was right.

I'm not sure there are stick shaker on airbus (AF447 you cite).

@ManuH I did not use 447 as an example of a shaker, but as an example of how crews but can fooled into believing something is happening when the opposite is true.

PC-12 has a pusher, too

@casey: Why do they still emphasise "minimal altitude loss" for stall recoveries when all this does is give pilots the dangerous impression that they can simply "power out" of a stall without pitching over to reduce the aircraft's attack angle?

The Australian Transport Safety Bureau recently published a comprehensive research paper on reported stall warnings in high capacity aircraft - http://www.atsb.gov.au/publications/2012/ar-2012-172.aspx
The report says that 30% of all stall warnings were false. Note that stall warnings aren't limited to the stick shaker.
The report says that of all reported stick shaker events, 16% were false warnings. Have a read of it, you'll find lots of interesting bits of information.

False positives are better than false negatives in a shaker. I'm curious how many times the shaker should have gone off and didn't.

The difference between stall buffet and mach buffer is known as the "coffin corner." I thought most modern aircraft had fairly large (50+kt) differences, and was surprised to read that it is as low as 20kts. ( http://en.wikipedia.org/wiki/Coffin_corner_(aerodynamics) )

How reliable are stick shakers? Should they always be trusted?

I think the answer to this is can be covered by one of the great aviation mantras:
"always trust your instruments"
This is drilled into you when learning to fly on instruments. Pilots very rarely rely solely on one source of information. If you get a stick shaker, you'll normally immediately look for the reason as part of your scan. Stall warnings are rare in large aircraft but you sometimes get transient warning, e.g. when an aircraft is in turbulence or at low speed with a higher angle of attack and manoeuvring.
The crew of AF447 had a number of conflicting indications in the flight deck and were relying on the protection system of the aircraft to prevent the stall. Sadly the aircraft ended up stalled as the protection systems were not functioning correctly due to an erroneous air data source. One of the pilots held positive back pressure on the controls which maintained the stall condition of the aircraft. The recovery from the stall in large aircraft is the same as any with the most important part - Lower the nose.
Good article by Boeing here
Stick pushers are rare now as aircraft designers tend to shy away from producing aircraft which require one. Aircraft such as the HS Trident had stick pushers as they could end up in a deep stall - which is unrecoverable flight condition.

Roger Roger.  I think this confirms what I'm thinking.  Stick shakes, no matter what anyone else is telling you, push it.  I did rather complicate things by referencing 447 which I used as an example of fixation, rather than of stick shake.

I think it's important to analyse all of the information you are presented with. If the stick shaker is going - why? Justify your actions, act and then feedback the results to reanalyse the condition.

The flight envelope protection of Airbus and Boeing 787 is a stick pusher and more (it allows you to fly reliably on the edge of stall—e.g. when you find yourself in downburst and need to stay as high as possible).

I don't think they have stick pushers in the traditional sense. The old stick pushers literally pushed the yoke forward to lower the nose and help recover the stall. Modern fly-by-wire aircraft have Alpha protection, called alpha floor on the Airbus. This limits the angle of attack and applies Take Go / Go Around thrust.

I'm going to lump stick shakers with all stall warning devices as they all have the same purpose. Stall warning devices are extremely reliable, and often more reliable than many pilots' judgement. When they go off it is because the conditions for a stall exist, and action should be taken. Occasionally a stall warning will go off momentarily in level flight because of turbulence, that usually is so short no action could be taken before the warning goes away.
Humans often have trouble in re-evaluating situations and can become fixated on one theory of events, especially under stress. People like to have confidence in their beliefs and judgement which leads to confirmation bias, where people "cherry pick" details which fit their model of events. This can lead people to ignore information that is literally in their face, as in AF447, Northwest 6231, and other similar accidents. The airplane can be shouting "STALL! STALL!", with an air horn blaring, stick shaker vibrating the pilot's hands until numb and the pilot will still be wondering why there's a high rate of descent.
So always trust your stall warning. Personally (I'm a light aircraft, not a commercial pilot) I practice stall recovery often where I immediately recover on the buzzer/horn, I do this so that it will become an instinctive reaction which I will do even if I'm overloaded and confused.

In a fully developed stall no pilot should be wondering about a high sink rate, or she/he better hands back her/his license. Immediately.

Thanks GdD.  This is pretty much what I figured.  I'm a heli pilot so stall warnings are alien to me.  If you stall a helicopter, there is NO recovery ;)


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Could the CVR and FDR record to the cloud?
Another enthusiast question. I watch a lot of the National Geographic Channel's "Air Crash Investigation", for better or worse, and it seems accident investigators make tremendous use of the Cockpit Voice Recorder "CVR" and Flight Data Recorder "FDR" to determine the chain of events leading up to- or the root cause of an accident.
One of the more recent episodes of ACI (Season 12 Ep. 13) was about Air France 447, the worst disaster in French aviation history. That investigation spent two years and $50 million just locating the CVR and FDR which were ultimately found resting 4 kilometers beneath the mid-Atlantic. Even after the recovery, there were concerns one of the drives had failed.
That ACI episode also mentioned that the Airbus A330-203 in that accident came equipped with a system which periodically transmitted maintenance data to a remote Airbus location in Paris to alert ground crews of possible maintenance issues with inbound aircraft.
Given that Airbus already uses similar technology for maintenance data (and I think I recall hearing Boeing does too), I was wondering if either Airbus, Boeing, or the FAA, plan to facilitate or mandate that the CVR and FDR record to the cloud or a remote location either in lieu of or in addition to the physical devices installed in commercial aircraft. I would think this would be an accident investigator's dream come true, with almost instant access to vital investigative information, while drastically reducing instances of going without these crucial tools when the physical devices are unrecoverable.
So, does anyone in the know have any idea if there are plans for CVR and FDR data to be transmitted and recorded to the cloud or a remote location?

@pondlife I removed the tag airline-operations from this question because FDR's and CVR's are not specific to the airlines.  (I have them in the airplane that I fly! )

@Lnafziger Good point, ironically it's probably more practical - in purely technical terms - for a C172 driver to stream flight and maybe even voice data from his iPad than for an airliner to do it, for the reasons you've explained.

Actually the BEA recommendations on that specific topic includes: "study the possibility of making it mandatory for airplanes performing public transport flights  to  regularly  transmit  basic  flight  parameters  (for  example  position,  altitude, speed, heading)". Many solutions were evaluated for their feasibility and cost by the working group. Solutions similar to the one you suggest have been studied but are not yet mature. See the linked report for additional details.

https://airtrafficmanagement.keypublishing.com/2019/02/08/honeywell-curtiss-wright-to-use-connectivity-to-reinvent-black-box/

The basic problem with transmitting CVR & FDR data to the ground from flight is the sheer amount of data that is generated by today's sophisticated airplanes.  There are hundreds of parameters being recorded many times per second plus the voice channels.  Today's airliners record 500 GB of data on each flight.  Take this and multiply it by the thousands of airplanes that are in flight at any given moment, and you can see that there would need to be a lot of bandwidth available for all of it to be transmitted wirelessly.  There would also need to be a world-wide standard developed and hardware deployed so that an airplane can transmit the data no matter where they are.  Airplanes operating in remote locations would have to use satellites, which are relatively low speed and expensive to deploy/maintain/operate.
In short, it just isn't practical with today's technology.

All it would take is for Airbus or Boeing to try it out, possibly with low-fi recordings or only partial data inputs/parameters and the technology would improve. In the case of Air France 447 it would've saved two years and $50 million–that's pretty serious time and money. "Isn't practical" doesn't seem like a great justification for marginalizing like this. (That's not a personal attack on you, but lots of things seemed impractical at inception and were tried, improved upon, and have now evolved to be commonplace.)

@cfx It costs a lot more than that to launch even one satellite, much less a world-wide system with the capacity to do this.  (See: http://www.globalcomsatphone.com/hughesnet/satellite/costs.html).  Trust me, there are a lot of people who are looking into this, and there was at least one study specifically on the Air France accident that focused on the feasibility of such a system.  The technology just isn't there yet.  They do already transmit some data, but to do it at the speed of the FDR can't be done yet, especially on oceanic routes.

That was more along the lines of my question. Is it being done or investigated, not whether it's feasible. Thanks for the follow up comment–that would probably make a better answer.

@cfx Well, the studies have shown that it isn't practical/feasible (which was the whole point of my answer and I shared some of why it isn't feasible).

Yesterday/today's events re Malaysia Airlines' missing 777-200 (http://www.cbsnews.com/news/malaysia-airlines-loses-contact-with-plane-en-route-to-beijing-with-239-aboard/) echo those of the Air France flight I mentioned. Hope it doesn't take two years to find out what happened. Even minimal cloud recording of FDR and CVR would be helpful in cases like this. Thoughts and prayers with the families of those onboard.

@cfx: Someone on board of MH370 apparently made conscious effort to stop even the data transmission that exists. If the aircraft transmitted more data, they would have stopped that transmission too anyway.

The article you link does not mention the FDR; it seems more likely that's on the QAR, and the FDR records far less. Also, the article emphasizes two things: how new and unusual it is to deal with so much data, and how connected the plane is while in flight. The article really doesn't back your claim very well.

But it wouldn’t be transmitting from the air to the ground, it would be transmitting to the cloud.  The only problem would be how would the data be recorded when the weather is CAVU?

Is it still practical with the technology that is available today?

@Valay_17 with Starlink and OneWeb and some more it is now starting to be viable to be sending at least voice + basic flight parameters + alerts. There will be some privacy concerns though, at least in the West.

@cfx low-fi voice is not necessary; 16-bit 48kHz sample rate PCM audio (well above communications quality) for 20 hours is only 115 MB of data. Voice data is a tiny fraction of the 500 GB. This is obviously an extreme case that would never happen, but you could record an audio stream at this quality for each seat in an A380 on this flight in under 60 GB. Of course, there will not be nearly this many streams in reality; I'm not sure how many channels CVRs record, but I expect just a few, if more than one. Also, 8 bit 8 kHz recordings take 1/12 of the space and are still fine for voice.

Could we record everything to the cloud? No. For one thing, we just don't have the storage capability and communication bandwidth. Transmitting data from a plane travelling at mach 0.85 over the atlantic is no mean feat: we've managed it, but it isn't like a home fibre connection running at a steady 100Mbit/s or more.
Add in the fact that currently we aren't saturating the satellites right now... but if suddenly every plane was transmitting at full speed constantly, both the frequencies used, and the satellites themselves, would quickly be saturated. We would need a LOT of satellites and a much larger frequency band allocated to that transmission type.
Then there's storage: there are thousands of planes in the sky, recording several gigabytes of data per hour. Perhaps if we used a similar "keep 24 hours of data" strategy, this could be manageable.
On the other hand, we could, and probably should, transmit and record some data, or at least more data than we do now. At the very least, we should be able to transmit basic telemetry and control input positions, along with perhaps a little information regarding engine power settings etc. They wouldn't necessarily be up to the level of the Flight Data Recorder of Cockpit Voice Record information, but it would at least give us something to work with.
Since MH370, there's talk of ensuring we, at the very minimum, know the location of every aircraft in close to real time, so if nothing else we should be able to localise the search area faster in future.

I agree wholeheartedly, however there's the whole 'everything electrical has a fuse' issue, so that would/could have defeated the system for MH370. A possible solution might include no transmission until an anomaly is detected, then starting, say 5 minutes ago (from the FDR/CVR), start streaming all data until the situation is resolved or the device can no longer transmit. That would significantly reduce the amount of data to be transmitted, as only 'situations' would be transmitted.

@freeman define anomaly? MH370 is a very unusual case - typically the aircraft hits something solid/close enough to solid (usually the ground or see) and then we have to find the recorder - in that case, there's no anomaly to detect. Admittedly it would have probably helped for MH370, but not for many others.

Since this just bubbled to the top again- "anomaly" triggering probably wouldn't have helped for MH370 (fuses can be pulled). However, if there's an engine out, loss of pressurization, or any other mechanical failure that would cause any sort of alert in the cockpit (OK, maybe not a "toilet not flushing" warning), that could be considered an anomaly that would trigger the beginning of FDR/CVR transmission. For AF447, for example, if it had been transmitting from the moment the stall warning went off, the time spent looking for the FDR/CVR would have been saved.

Commercial aircraft do transmit a limited amount of data via ACARS. This information can only be received line of sight, so if the aircraft is over the ocean the information will not be received (except by a ship that might be randomly listening).
The information on a flight data recorder is stored to a tape or other high-density storage and contains gigabytes of information. It would be impossible to transmit this much data via a normal radio due to insufficient bandwidth. You could potentially transmit this much data with a microwave link, but this would require a complicated satellite-based system. Military drones, like the Global Hawk, do make such transmissions (the big dome on top is the microwave antenna). Even if you equipped commercial aircraft with such bulky transmitters, you would need to launch thousands of new satellites to listen to and receive all the transmissions from the thousands of planes. So, while it may be technically possible, the cost and complexity of such a system is way beyond what is currently viable.

Wikipedia says that ACARS can also be transmitted via HF or satellite, in which case it could send from over the ocean.  I thought that was the case with AF447.

Ships might be able to receive ADS-B if the right equipment were installed (currently ships have no reason to do this) - but how would ships intercept ACARS? isn't it directed at satellites when over ocean?


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Is a Cessna 172S still airworthy if factory-installed instrumentation not required for day VFR flight is inoperative?
A C172S I occasionally rent had the EGT gauge placarded INOP when it had a JPI EDM-700 engine monitor installed. The placard sits on the gauge so you can no longer see the needle. Probably the single point EGT probe has been removed so the needle wouldn't work anymore. Of course that is fine - the EDM-700 is TSO'd.
Now recently the EDM itself is placarded INOP and its circuit breaker collared so it cannot be reset.
So now this 172S has two INOP EGT gauges, and I'm down to leaning by ear. I know the EGT gauge is not required daytime VFR equipment. However, since the airplane was certificated having a factory EGT gauge installed, I'm wondering whether it's airworthy like this. The Plane is N-registered and I'm asking within FAA jurisdiction.

Closely related

Part 91 does not require an EGT probe for any operations so the next thing to look at is your AFM.
Your C172S has an AFM that includes a Comprehensive Equipment List. It is probably similar to this one that indicates that the EGT probe is standard equipment—not required for certification, this airplane can fly with it placarded.

The 172S has both a Comprehensive Equipment List and a Kinds of Operation List in the POH. Check them both to see if you can operate the aircraft without an EGT. My guess would be yes, since practically, it does not NEED it. You can lean the engine using the Tach and your ear. And, 91.205 does not require an EGT nor a CHT.

Ours is one year before they did the Kinds of Operation List. But it doesn't make any difference.

It’s airworthy if the gauge reaches here are not required for the operations in question per 91.205 and the procedure outlined in 91.213 is used to label the gauges inoperative AND this problem is addressed and repaired during the next maintenance session.


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What are the advantages and disadvantages of an oblique wing over a swing wing?
This question asks about the benefits of an oblique wing over a delta wing, but I am more interested in the benefits of an oblique wing compared to a swing wing.
Wikipedia states:

This is a variation on the classic swing-wing design, intended to simplify construction and retain the center of gravity as the sweep angle is changed.

But I'm pretty sure there are a lot more advantages or disadvantages, in terms of stalling behavior (forward swept side inboard first, aft swept side outboard first), aircraft control etc.
Related: What are the advantages of a forward-swept wing over a rearward-swept wing?

Advantages of an oblique wing over swing wings:

Low wave drag due to favorable volume distribution over length.
Lower structural mass. The hinge of a swing wing is heavy!
No shift in the center of lift (if the sweep angle is higher than the Mach angle). A swing wing experiences a severe shift in the center of lift.

Disadvantages of an oblique wing over a swing wing:

One wing is swept forward, the other aft. This is no problem in straight flight, but when maneuvering, it will behave in odd ways because the axes of its inertial system are not aligned with the direction of flight.
Aeroelasticity: Gust response when flying oblique will include a roll answer, because the forward-swept wing will twist to a higher angle of attack in a positive gust, increasing lift, whereas the backward swept wing will twist to a lower angle of attack (aeroelastic washout).
Wing-airframe integration is complex, and the wing needs to be on top of the fuselage (unless you have a flying wing; then the disadvantage is a really small payload volume). The swing wing needs much space for the hinge, spar carry-through and actuation, but can be placed anywhere you like.

Note that all other effects which plague the forward-swept wing apply here, too, but only on one side. The effect of boundary layer thickening will only happen on the backward-swept side, so changing the angle of attack will already create a rolling moment. The oblique wing will only behave normally when set at a sweep angle of 0°.

Good answer! About your second argument, wouldn't the hinge (or pivot) of an oblique wing also be very heavy?

@ROIMaison: This is in comparison to a swing wing. Of course, a straight carry-through without hinge is the lightest solution. But the oblique wing needs only one hinge in the interface between fuselage and wing. I changed "low" to "lower"; now it makes more sense.

The oblique wing and the swing wing aim to reduce the drag over a wide range of speeds by changing the wing sweep. While the swing wing rotates a part of the wing to achieve this, the oblique wing rotates the whole wing.
The first production aircraft with variable sweep wings was the F111 Aardvark, while the most famous one is the F-14 Tomcat.

"F-14 Tomcat prototypes in flight c1972" by U.S. Navy - U.S. Navy National Museum of Naval Aviation photo No. 2011.003.301.027. Licensed under Public Domain via Commons.
However, the only full sized aircraft to be produced with an oblique or pivot wing was the NASA AD-1, which was strictly an experimental aircraft.

"AD-1 ObliqueWing 60deg 19800701" by NASA - http://www1.dfrc.nasa.gov/Gallery/Photo/AD-1/HTML/ECN-15846.html. Licensed under Public Domain via Commons.
A comparison between the two can be made like this:

Aerodynamics: The oblique wing is much more refined aerodynamically compared to the swing wing and had lesser drag. In fact the AD-1 was designed to be as close to the optimal for all the flight regimes. Also, the aircraft was designed to have an elliptical lift distribution to reduce induced drag. on the other hand, the variable geometry aircraft did not offer any significant advantages over fixed wing baseline aircraft.

However, the asymmetric stall of the oblique wing aircraft would cause problems as one side of the wing is swept forwards and the other side is swept towards the rear.

Structure: The hinge was arguably the most critical structural part in variable sweep wing aircraft. The hinge should not only have a very high reliability, but also have the capacity to bear the high aerodynamic loads.

"Tornado variable sweep wing Manching" by Sovxx - Own work. Licensed under CC BY-SA 3.0 via Commons.
In this case, the swing wing aircraft are better off compared to the oblique wing aircraft as the amount of load on the hinge is significantly lower.
For example, the oblique wing hinge has to take not only the weight of the entire aircraft wing (the swing wing aircraft typically rotate only a part of the wing), but also the entire fuel load (the amount of fuel carried in the variable part of the wing is significantly small). Also, the hinge should take the load of the control system too.

Handling and Controls: The handling of the swing wing aircraft have been brought closer to the fixed wing aircraft over time. However,the handling qualities of AD-1 was found to be poor, with unusual trim requirements and inertial coupling affecting the aircraft negatively.

For instance, the AD-1 required about 10° of bank in order to trim the aircraft with no sideslip at 60° wing sweep.The aircraft also experienced pitch-roll coupling and the associated aeroelastic effects made for unpleasant handling qualities above 45 degrees sweep.
One advantage of the oblique wing aircraft is that the center of lift and mass doesn't move as the wings are swept. This happens in the swing wing aircraft and the control system is complicated

Engine and payload In case of swing wing aircraft, the engines can be mounted in the fuselage (like F-14) or in the (fixed part of) wing itself (like B-1). In case of the oblique wing aircraft, locating the engines anywhere except the fuselage is effectively ruled out.

In case of military aircraft, use of hardpoints in the variable point of the wing is limited (for one thing, this will increase the load on the hinge). This is a much more serious problem for oblique wing aircraft as this limits the payload that could be carried.
However, the main reason for the lack of further development of oblique wing aircraft is their unusual and unpleasant control qualities.

The hinge of a swing wing needs to transmit lift and bending moment, while the central hinge of the oblique wing only needs to transmit lift. How can the oblique wing hinge be heavier than two swing wing hinges?

@PeterKämpf: For most swing-wing airplanes, a large part of the airplane's lift is generated by the fixed inboard portion of the wings and by the fuselage (the vast majority of swing-wing airplanes, like the B-1 and F-14, are blended wing-body aircraft, where the fuselage produces considerable lift), greatly reducing the amount of lift carried by the outer wings and transmitted through the hinges.

@Sean: The F-14 and B-1 are later developments and profited from the experience with the F-111 which had its hinges more inboard. Their movable wing portion was held as small as possible. Also, at low angle of attack, even the B-1 and F-14 still generate most lift with the movable portion of the wing.

The oblique wing has been studied as yet another way to improve the speed envelope and/or fly more efficiently at higher airspeed.  It was intended for long distance cruising application, but never was able to make any headway against what is universally seen in modern designs, change of camber.
It is honestly surprising that even rudimentary slats have not found their way into mainstream application yet for recreational aircraft, as combined with flaps, they produce huge amounts of lift, enabling very low take off and landing speeds.  Probably one of the finest examples of a successful light aircraft design that employed slats was the Fiesler Fi 156 Storch.  Slats, along with slotted "doppel wing" flaps make the Storch an outstanding STOL aircraft, making them retractable would enable better cruise performance, as airliners do.
Changing wing geometry, as seen in the B1 bomber, is still useful in the application of providing a wider range of ALTITUDES for high speed cruise.  The B1 can go high with wings extended, or low with wings back.
Survivability in these times favors going low.
The oblique concept did improve high speed cruise efficiency, but never found an application niche where it was clearly better than changing camber or sweeping both wings back.  It did not sell.
There is one possibility that may be of interest.  That would be FULLY rotating the wing parallel to the fuselage and flying on the tail and canard only.  In the days of sail, in high winds, the mainsail was dropped, and the fore and rear sails were used only.  This was referred to as sailing "jib and jigger".
The reduced wing area would lower lift and drag considerably, allowing for much higher, perhaps supersonic speeds.


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Does ADS-B In receive track or heading angles?
I am reading this: https://mode-s.org/decode/ehs/bds50-track-n-turn.html
I am wondering the Track angle which ADS-B In recieve is really the track angle (derived from line joining the previous and current point) or the heading angle (or its body angle)?

The document you linked says "true track angle". What exactly is unclear to you?

@Bianfable I am just wondering how this "True Track Angle" is being produced, whether they are derived from GPS track angle or from instrumentation IMU heading. Or whether they are filtered through Kalman Filter and combined from various sources

It is the true track angle.

True means with respect to the geographic North (as opposed to the magnetic North)
Track angle means the direction of motion in the horizontal plane (as opposed to heading, which means the direction of the projection of the primary body axis in the horizontal plane).

Track angle can be derived from a line joining successive position points, but that is not typically how its done. GPS commonly uses a combination of Kalman filtered change of position combined with (Kalman filtered) velocity derived from Doppler shifts.
For ADS-B In, the track angle is just what is reported by ADS-B Out. It does not involve processing successive position reports.

Thanks for your answer! Was confused over the difference heading angle and track angle. Seem like they mean the same in this case

If I'm not mistaken, the heading angle can differ from the track angle if the plane has to compensate for the wind to fly in a certain direction, e.g. crabbing in a windy landing.

The link you provided appears to be an article combining ADS-b with Enhanced Mode-S. It has three sections and an intro. The “Track Angle” and “Roll Angle” information is in the Enhanced Mode-S section, and NOT the ADS-b section.
Are you asking about the data displayed for the other aircraft displayed on your ADS-b in? The above answer sums it up.
Additionally, ADS-b does not transmit attitude and heading information to other ADS-b receivers and ground stations. Any AHRS data calculated by an ADS-b unit is only for the use of the aircraft in which it is being used (ownship). Also, that info is not considered accurate for flight and navigation purposes. It can not be used except as a supplementary reference. Legally, it can not even be used as a backup to your TSOed, panel-mounted instruments. Although, in an emergency, something is better than nothing.
The information that ADS-b transmits is based on GPS data. GPS would give you the aircraft’s position (including altitude) and track (including trends) regardless of its heading and attitude. It transmits this information to aircraft’s airborne receivers and ground stations for rebroadcast automatically, without being interrogated.
An Enhanced Mode-S Transponder, when interrogated, transmits its information to ATC’s secondary surveillance radar. Along with its normal Mode-S information, Enhanced Mode-S can transmit specific Downlink Aircraft Parameters (DAP) when requested. This information is provided by various aircraft sensors. Some of these DAPs are:

roll angle
true track angle
ground speed
track angle rate
true airspeed

Hi, you are right in that I am asking more about Enhanced Mode-S. Is it by regulation and law that all aircraft must transmit ADS-B or ADS-B Enhanced Mode-S. Also you have mentioned "that info is not considered accurate for flight and navigation purposes", is it due to ADS-B being a delayed information or?

The information that I mentioned that is not intended for flight nor navigation is the AHRS information that you can get from some ADS-b in devices. Those devices can give you heading, roll, and pitch. But, it is not a certified source of this information. ADS-b out does not have that info by itself.


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If I'm cleared to land without any specific instructions on how to enter the pattern, what should I do?
I learned at an uncontrolled airport. I thought I had controlled communications down pretty well, but I upset the tower controller today.
Situation:
I was coming from the southeast, and tower told me “clear to land runway 5”. He didn’t tell me what leg to fly or anything. It wasn’t busy. So I stayed straight for the left crosswind. He said I should have never crossed the field. I continued left downwind, base, and final.
I know I should have asked for clarification on how he wanted me to enter. Maybe he was also expecting me to have maneuvered to the west side of the airport for a right base.
I could use some coaching on this. What do you all experienced pilots think?

What country is this in? I know that flying in certain areas, you are expected to include the upwind and downwind in your inbound traffic pattern. The US is not one of them. None that I know of advocate joining the traffic pattern on the crosswind. Why did you just not join the left downwind for runway 5 at a 45° angle (initially a right turn) if you were coming from the Southeast?

By the way, welcome to AviationStackExchange. Please, don’t take my comment above too harshly. I am sincerely trying to understand your thought process or the training you received so that I can help answer your question.

Which airport was this?

It might be worth a phone call to the tower to ask them what they expected as well as learn from the answers here.

@DeanF.  Arriving from the southeast - heading northwest - a right turn will put you on a left upwind for rwy 5. Generally, I would expect the tower to tell me where to join the pattern (and the direction), provide vectors to final, or indicate a straight-in approach. If ATC instructions aren't clear, ask for clarification.

@Gerry - You are absolutely right. I had it reversed in my mind.

In the UK, my opening call to a full ATC tower is for joining instructions, though I'll usually have read-up on the published patterns.

I just wanted to thank everyone for the helpful comments.  I also asked my previous flight instructor.  I have learned so much from this thread!

Your description sounds like the diagram below, so I'll proceed based on that.
When a controller gives you a landing clearance while you are a ways out with no intermediate instructions, it's usually because there is nobody else around the controller needs to coordinate and you are being given discretion to proceed by the most direct logical routing to get to the threshold of Rwy 5.
Although there is a published "left" traffic pattern, and normally you would follow the usual protocols to get established for the left pattern for Rwy 5, the landing clearance at that stage was granting you discretion to use a right pattern if it was more direct and that's what the controller expected. When you crossed the field to get to the "proper" side (blue line below), this would get the controller wondering what you're up to as you appear to be just flying off to the northwest until you turn downwind, especially if you are in the habit of using wide patterns.
I would have proceeded direct to a right downwind or even a right base leg (red or black line below) if I was already line up for that, and would have mentioned that in the readback for the landing clearance, such as "Cleared to land runway 5, proceeding direct right base", just to let the controller know my intentions, and if there was a misunderstanding, I'd find out about it then.
There is a contributor here who is an air traffic controller, so hopefully he/she will chime in.

In the UK the blue line is somewhat near to what we call an "Overhead Join" - which is the SOP for the left circuit (pattern) given no other instructions.

Same in Canada.  In the absence of ATC, like when the tower is closed, overhead to the left circuit that would be what to do.

This appears to have been a good learning experience for both you and the controller. It seems you both made assumptions which were different for each party.
At a tower controlled airport you must follow the controllers instructions regardless of any published circuit pattern. You say that the controller only said "clear to land runway 5". Was there no other communication after that by either you or the controller? This is either an error by the controller, or you missed part of his instruction.
It is normal to expect the shortest route to the runway at a tower controlled airport. When approaching from the southeast, most experienced pilots would expect a clearance to right base followed by a landing clearance.  The controller should have given you an instruction which included how to join the circuit. The controller should have said "join right base, cleared to land runway 05".
In the absence of an instruction or clearance to right base, you should have asked for clarification. Even if he did indeed only say "clear to land runway 5", you should have confirmed how to join the circuit.
You made an error by overflying the airport without a clearance or instruction to do so. Good airmanship dictates that you should have at least reported your intention to join the circuit either crosswind or overhead. It never hurts to announce your intentions or position. It only increases situational awareness for everyone.

In the US, there are several ways to approach a runway for landing that are generally accepted. They include, but are not limited to:

Instrument approaches
Visual Charted approaches
Overhead approaches
Circling approaches
Straight in approaches
Surveillance Radar Approaches
No-Gyro approaches
Visual approaches
Contact approaches
Side-step approach
Base-to-final
Traffic pattern approaches

If you choose or are directed to fly the last approach on this list, there are five generally recommended ways to join the traffic pattern dependent on which side of the traffic pattern you are arriving. They are:

Arriving from the same side of the runway as the downwind leg? Directly join the downwind leg at traffic pattern altitude, at a 45° angle.
Arriving from the same side of the runway as the upwind leg? Cross the upwind leg and the runway at traffic pattern altitude, at a 90° angle at midfield. Directly join the downwind leg.
Arriving from the same side of the runway as the upwind leg? Cross the upwind leg, the runway, and the downwind leg 500 to 1000 feet above traffic pattern altitude, at a 90° angle at midfield. I prefer 1000 feet since large and turbine aircraft are recommended (sometimes required at some airfields) to fly at 500 feet above normal traffic pattern altitude. Continue to fly one to two miles away from the downwind leg. Affect a 270° descending turn in the opposite direction of the downwind leg. Join the downwind leg at traffic pattern altitude, at a 45° angle.
Arriving from the same direction as a straight in approach? Join the upwind leg at traffic pattern altitude at the extended base leg. Continue to parallel the runway until midfield. Cross the runway at a 90° angle at midfield. Directly join the downwind leg.
Arriving from the same direction as a straight in approach? Join the upwind leg at traffic pattern altitude at the extended base leg. Continue to parallel the runway until crosswind. Turn crosswind. Turn to join the downwind leg.
Arriving from the reciprocal direction as a straight in approach? Remain on whichever side of the extended center line of the runway your original course has placed you. Carefully widen your distance from the extended center line. Alter your course enough to place you in a position to use one of the first 3 traffic pattern entry options.

ATC is going to direct you to use one of these types of approaches (except for the contact approach). Follow their directions. If there is any information missing, ATC is going to expect you to use the approach that is most expedient to affect a landing. But, if in doubt, ask them for clarification.
Note that none of the above approaches has the aircraft entering the traffic pattern at crosswind. Crosswind at traffic pattern altitude is the most dangerous place in the traffic pattern an aircraft can be. Both the pilot and ATC should limit the amount of time in the crosswind leg as much as possible.
Remember, like driving, the safest way to fly in an area of possible traffic is to fly as predictably as possible. Try not to go outside of the norm. And, if you have a particular approach style you want to do, ask for it. Or, at least inform ATC and your fellow pilots to expect it.

As a controller (edit: USA) I would say there isn't a "published" traffic pattern at a towered airport. I generally am aware that at uncontrolled airports, or when the tower is closed, left-hand patterns are standard. But if the tower is operational the tower is responsible for keeping planes apart and we don't favor one side over the other just because it's "standard." We favor one side over the other based on what the most direct entry would be or where other traffic is or is going.
I would 100% be surprised and upset if you entered the left downwind in that situation. But I also agree that you should have gotten a pattern entry from ATC, either from approach (if class B or C) or tower (if class D).

If the controller didn’t specify, then I would take that as them not caring. I’d set up for the near-side downwind, the near-side base or the straight-in depending on where I was in relation to the runway because that’s the easiest and fastest (read: laziest and cheapest) thing to do, and that’s what ATC will be expecting.
Notice that crossing the runway to the far-side downwind is not on my list, and regardless of whether that’s legal (I have no idea since it never occurred to me), it’s definitely a Bad Idea™ to surprise ATC.
If you are ever in doubt about what ATC is expecting you to do, just ask. They’re there to help you, after all, and the best way to do that is to make sure you’re both on the same page.

My ten cents on this one: I was always taught that you fly all patterns as left handed, unless specifically cleared otherwise by ATC. Then again, I was always told you never cross the runway, on ground or in the air, without clearance. The reason for not crossing the runway is, that the ATC may have cleared a plane for takeoff, and if someone was to fly (or taxi) across the runway, separation might be lost.
I may have been taught wrong, but things were beautifully simple that way. Good old days...
As mentioned above, a very good learning experience for both parties. You had different mental pictures of how things will go, and were surprised. No casualties, so it's a win-win if you both learn something.

You shouldn't just assume that the runway has a left-hand traffic pattern. Sure, probably 90% of them do, but that's not a guarantee. You should always look up which traffic pattern a particular runway uses before you fly there, or use the pattern markers next to the runway (if available).

I omitted the obvious, which is that during flight planning you check out if there are such  irregularities as rh pattern ;)


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What are the primary and secondary flight controls for the SEPECAT Jaguar?
What lift augmentation devices are used in the SEPECAT Jaguar? I couldn't find any information.

According to  airvectors.net, the flight controls of the SEPECAT Jaguar are:

The Jaguar A had a high-mounted wing with a sweep of 40 degrees and an anhedral droop of 3 degrees, with relatively small wing area for a smoother ride at low altitude. There was a leading-edge flap along the outboard section of each wing, and large, double slotted trailing edge flaps on both the outboard and inboard sections of each wing. There was a "dogtooth" between the outboard and inboard sections of the wing.
There were no ailerons, roll control being provided by a two-section spoiler on top of each wing, just forward of the outboard flaps. There was a prominent "fence" between the inboard and outboard sections of the wing. Along with a conventional tail assembly, with all-moving one-piece tailplanes, there were two ventral fins. There were twin hydraulically-operated perforated airbrakes ahead of the ventral fins, under the wings. The hydraulic system was dual-redundant.

(Emphasis mine)
The omission of ailerons from a ground attack fighter might seem odd, as one might presume this makes the plane less  maneuverable. But, as described in the first sentence of the quote, the Jaguars main mission was to (or at least it often had mission critical sections with) flying fast and low, which often translates into a very choppy ride. This was mitigated by the use of a smaller wing = higher wing loading. To achieve low enough approach and landing speed with such a small wing, efficient and large flaps were needed. As sufficient and consistent roll control is somewhat hard to achieve with flaperons (or at least it was when Jaguar was designed), the Jaguar had to make do with full span flaps and use spoilers for roll control.

Looks like there is a dog-tooth leading edge and no slats, with flaps at the inboard trailing edge.
Edit: Notice how the stabilator tailplane is trimmed, as well as the ailerons.